Faculty Opinions recommendation of Action potential duration restitution and alternans in rabbit ventricular myocytes: the key role of intracellular calcium cycling.

2007 ◽  
Author(s):  
Godfrey Smith
Keyword(s):  
Action Potential ◽  
Intracellular Calcium ◽  
Action Potential Duration ◽  
Ventricular Myocytes ◽  
Calcium Cycling ◽  
Rabbit Ventricular Myocytes ◽  
Action Potential Duration Restitution

scholarly journals Action Potential Duration Restitution and Alternans in Rabbit Ventricular Myocytes

2005 ◽  
Vol 96 (4) ◽  
pp. 459-466 ◽  
Author(s):  
Joshua I. Goldhaber ◽  
Lai-Hua Xie ◽  
Tan Duong ◽  
Christi Motter ◽  
Kien Khuu ◽  
...  
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Ventricular Myocytes ◽  
Rabbit Ventricular Myocytes ◽  
Action Potential Duration Restitution

Biphasic effects of cell volume on excitation-contraction coupling in rabbit ventricular myocytes

2002 ◽  
Vol 282 (4) ◽  
pp. H1270-H1277 ◽  
Author(s):  
Gui-Rong Li ◽  
Min Zhang ◽  
Leslie S. Satin ◽  
Clive M. Baumgarten
Keyword(s):  
Action Potential ◽  
Cell Volume ◽  
Action Potential Duration ◽  
Ventricular Myocytes ◽  
Current Clamp ◽  
Osmotic Swelling ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Fura 2 ◽  
Rabbit Ventricular Myocytes

We studied the effects of osmotic swelling on the components of excitation-contraction coupling in ventricular myocytes. Myocyte volume rapidly increased 30% in hyposmotic (0.6T) solution and was constant thereafter. Cell shortening transiently increased 31% after 4 min in 0.6T but then decreased to 68% of control after 20 min. In parallel, the L-type Ca2+ current ( I Ca-L) transiently increased 10% and then declined to 70% of control. Similar biphasic effects on shortening were observed under current clamp. In contrast, action potential duration was unchanged at 4 min but decreased to 72% of control after 20 min. Ca2+ transients were measured with fura 2-AM. The emission ratio with excitation at 340 and 380 nm (f340/f380) decreased by 12% after 3 min in 0.6T, whereas shortening and I Ca-L increased at the same time. After 8 min, shortening, I Ca-L, and the f340/f380 ratio decreased 28, 25, and 59%, respectively. The results suggest that osmotic swelling causes biphasic changes in I Ca-L that contribute to its biphasic effects on contraction. In addition, swelling initially appears to reduce the Ca2+ transient initiated by a given I Ca-L, and later, both I Ca-L and the Ca2+ transient are inhibited.

An ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes

EP Europace ◽  
2005 ◽  
Vol 7 (s2) ◽  
pp. S128-S134 ◽  
Author(s):  
Sarah N. Healy ◽  
Andrew D. McCulloch
Keyword(s):  
Action Potential ◽  
Safety Factor ◽  
Ventricular Myocytes ◽  
Reversal Potential ◽  
Ionic Model ◽  
Rabbit Ventricular Myocytes ◽  
Induced Changes ◽  
Transmural Heterogeneity ◽  
Action Potential Shortening

Abstract Aims To develop an ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes consistent with experimental observations, that can be used to investigate the role of these currents in intact myocardium. Methods and results A non-specific cation-selective stretch-activated current Ins, was incorporated into the Puglisi–Bers ionic model of epicardial, endocardial and midmyocardial ventricular myocytes. Using the model, we predict a reduction in action potential duration at 20% repolarization (APD20) and action potential amplitude, an elevated resting transmembrane potential and either an increase or decrease in APD90, depending on the reversal potential of Ins. A stretch-induced decrease in IK1 (70%), plus a small Ins current (gns=10 pS), results in a reduction in APD20 and increase in APD90, and a reduced safety factor for conduction. Increasing IK1 (150%) plus a large Ins current (gns=40 pS), also leads to a reduction in APD20 and increase in APD90, but with a greater safety factor. Endocardial and midmyocardial cells appear to be the most sensitive to stretch-induced changes in action potential. The addition of the K+-specific stretch-activated current (SAC) IKo results in action potential shortening. Conclusion Transmural heterogeneity of IKo may reduce repolarization gradients in intact myocardium caused by intrinsic ion channel densities, nonuniform strains and electrotonic effects.

The role of action potential duration restitution in vulnerability to reentry in a mathematical model of canine ventricle

Heart Rhythm ◽  
2005 ◽  
Vol 2 (5) ◽  
pp. S302
Author(s):  
Ashkan Hayat-Davoudi ◽  
Ali Baher ◽  
Yohannes Shiferaw ◽  
James N. Weiss ◽  
Alan Garfinkel ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Action Potential ◽  
Action Potential Duration ◽  
Action Potential Duration Restitution
Sign in / Sign up

Export Citation Format

Share Document